Currently, we convert image to Format_ARGB32. This means that on big
endian systems the order of bytes will be (0xAA, 0xRR, 0xGG, 0xBB).
However, in WebP library there is no function to import bytes in
ARGB format.

This commit makes us use Format_RGBA8888 and WebPPictureImportRGBA
on big endian systems, which will make the function work correctly.

qddshandler.cpp(483) : warning C4258: 'i' : definition from the for loop is ignored; the definition from the enclosing scope is used
qddshandler.cpp(477) : definition of 'i' ignored
qddshandler.cpp(467) : definition of 'i' used
qddshandler.cpp(486) : warning C4258: 'i' : definition from the for loop is ignored; the definition from the enclosing scope is used
qddshandler.cpp(477) : definition of 'i' ignored
qddshandler.cpp(467) : definition of 'i' used

The windows file seems to handle ce too in the new
version of libtiff. Only the <sys/types> include
and the not defined error handle were a problem.
The error handler ifndef _WIN32_WCE can be removed
as Qt builds libtiff without the gui integration.

Trying to build MNG image format plugin for WEC7 gives the error:
Cannot open include file: 'qmnghandler_p.h': No such file or directory

The correct INCLUDEPATH was already used in qmnghandler.pri, but it
wasn't included anywhere. Refactored mng.pro to use qmnghandler.pri
correspondingly as TIFF image format plugin uses qtiffhandler.pri

This is the collection of those earlier patches to libtiff in Qt that
are still relevant, updated as required. For details, refer to the git
history of the src/3rdparty/libtiff directory of Qt 4 and Qt
5/qtimageformats.

All defines which happened in tiffconf.h were commented in tif_config.h.

This commit removes the previous version of the bundled libtiff
(3.9.2), as well as all local modifications to it. It adds an
unmodified copy of the official libtiff source distribution, except
that various extraneous files have been removed, as usual.

The patches required to build it in Qt will follow in separate
commit(s).

When building with Visual C++ it would not detect the 3rd party
libraries because it does not include the lib prefix. So this now
accounts for this. Additionally console is added to the CONFIG line so
there is no need for a WinMain() function.

Currently only qtbase includes the required LICENSE files, which
are referred to from the code headers. The same files should
be distributed as part of all the modules as well, so that the
(L)GPL licenses are adhered.

libmng delivers the last animation frame with a 1ms delay, and delivers
an extra blank frame after that with the proper delay time, but this
confuses QMovie when QMovie::cacheMode() == QMovie::CacheAll.